1. Field of the Invention
The present invention relates to a molding installation using a die and, more particularly, to an automatic molding installation or the like having a layout suitable for automation of a die exchanging operation, a die conveying operation of a die to be set in a molding apparatus and so on.
2. Description of the Prior Art
Conventional molding equipment using a die includes one, for example, for a metal mold casting, a press molding, and a plasstic molding. As a plastic molding is known an injection molding, a compression molding, a blow molding and so on.
Molding apparatuses of various types for those moldings are known to those skilled in the art and they require a lot of time and labor in a die exchanging operation. A die is so heavy that it is very difficult and risky to exchange the die using labors only.
Heretofore, various methods have been employed for exchanging a die for an old one in a molding apparatus. For example, Japanese Utility Model Publication No. 2,537/1983 discloses a die exchange using a crane. This technology would be effective in an automatic conveyance of the die to the molding apparatus from a stocker in which the die has been stored although it would be effectively applicable to the die exchanging operation. The disadvantage prevailing in these technology using a crane system, however, underlies in the fact that a long time of labor work involving risk is inevitably required for hoisting dice with cranes.
Different technology is disclosed in Japanese Utility Model Publication Nos. 2,537/1983 and 5,557/1984, Japanese Patent Publication (Laid-Open) No. 48,132/1984 (Japanese counterpart of West German P3 222 743.4 and P3 242 169.9) and Japanese Patent Publication (Laid-Open) No. 201,624/1983 (Japanese counterpart of West German G8 212 045 and P3 220 911.8). These technology are directed to methods of exchanging a die through a table disposed on the side of a molding apparatus. This technology has the advantage that the die can be exchanged in a state of being loaded on the table without labor as required for conventional crane systems, thus leading to a stable die exchanging operation. It is to be noted that this technology is of some help to automating a die exchanging operation for a molding apparatus.
The Japanese Patent Publication (Laid-Open) No. 48,132/1984 and Japanese Patent Publication (Laid-Open) No. 201,624/1983 disclose an arrangement for a die conveyance means in a molding apparatus or on a die loading base in such a manner that a die is transferred between the molding apparatus and the die loading base through the die conveyance means.
It is to be understood that there is the merit that a series of the die exchanging operation can be automated in terms of the provision of stockers in instances where a die conveying carriage having a table with a die loaded thereon is disposed so as to connect the molding apparatus to the stockers.
In designing such a molding installation, it is desirable to dispose a maintenance area around the molding apparatus. From this reason, it is not preferred to arrange for a passage for the die conveying carriage close to the molding apparatus even when the die is withdrawn from the stocker using the die conveying carriage and the die exchange in the molding apparatus is carried out using it. For the arrangement as disclosed in those prior patent applications, it is designed that the conveyance means should be disposed capable of transferring the die in such a long distance as reaching both the stocker and the molding apparatus when the die is transferred from the stocker to the molding apparatus or vice versa using such a conventional conveyance means. The conventional conveyance means, accordingly, is rendered of a larger size and heavier weight as a matter of course. In the conventional arrangement where no maintenance area is disposed, a passage for the die conveying carriage can be arranged adjacent to stockers. However, a die conveyance means for introducing a die thereinto or withdrawing it therefrom should be mounted to each of a number of stockers, leading to a considerable expensive investment.
Recently, there has been particularly strong demands for an efficient die exchange operation. In particular, production of many different types of products in smaller quantities is currently in demand so that the number of the die exchanging operation has been required to be minimized and the die exchanging operation can be carried out as quick as possible without causing errors in exchanging a fresh die for an old one. In the event that a wrong die is introduced into the molding apparatus, the die may be caused to strike against the molding apparatus damaging both the die and the molding apparatus.
In automating an overall layout of a molding installation, an automation of a molded product withdrawing means should be taken into account. For a mold product withdrawing system, a molded product grip member for withdrawing a molded product from the molding apparatus should be exchanged in accordance with a predetermined type of the molded product in association with the exchange of a die adapted to form the predetermined mold product. As means on which the mold product grip member is loaded may be used an arm member. Such an arm member, however, presents the difficulty and complexity in its control system. The control system should contain a control of a position of suspension of the mold product grip member upon exchanging, a position of the arm member at the time of holding the molded product and movements relative to these control, thus rendering the control system complicated. It is also necessary to exchange a molded product grip member for another as quick as possible without errors as with the die exchanging operation.
When a plastic injection molding apparatus is employed as the molding apparatus, the gate cutting should be effected rapidly in order to shorten a molding cycle. In this case, an appropriate adjustment of clamping the die at the time of the gate cutting is essential.